The long-term goal of this project is to study the effects of different exercise modalities on Parkinson's disease (PD). PD is a disorder whose primary disability stems from motor dysfunction including balance. Recent studies have shown that the risk of falling in the elderly can be reduced through the practice of the Chinese CAMs such as T' ai Chi Chuan (TCC). This finding may be highly significant to PD. Although a recent report from Emory suggests PD patients can do well with aerobic (walk-run) exercise training (AET), it is still unclear whether the potential anti- parkinsonian effect of such modalities is secondary to improved physical fitness (CRF), motor control or both. CAM interventions such as TCC may offer unique opportunity to examine these fundamental questions. In PD we hypothesize that exercise training will reduce primary and secondary disability and that some of these changes represent reprogramming of central motor pathways. We will conduct a controlle, double-blind 16-week dose-response study of exercise based on caloric expenditure and thus on the cardiorespiratory fitness effects of exercise (CRF). The treatments will be Qi Gong (minimal caloric expenditure). TCC (low expenditure), and a walk-cycle AET (moderate expenditure). We will examine exercise-induced change in motor control using quantitative measures of motor disability, including dynamic gait and stability measures. We will also examine exercise effects on central and peripheral indices of parkinsonian motor disability. A caloric "dose-response" effect of exercise would suggest CRF is a major determinant of the antiparkinsonian effects of exercise. If the Chinese modalities are as effective or superior to AET, however, this would suggest that other mechanism such as change in central motor programming may by playing a role (e.g, relaxation effects, reinforcement of central motor programs?). A better understanding of exercise-induced neural plasticity and motor control would offer a significant, and heretofore unexploited rehabilitative potential in PD.